1. Field of the Invention
This invention relates generally to vascular stents for use in preventing restenosis of passageways and ducts in the body and to repair aneurysms percutaneously.
2. Description of the Prior Art
It is desirable that means be provided which will prevent the restenosis of a passage or duct due to the invasion of tissue between the wire struts of the stent. Such a situation often occurs where a tumor has invaded a biliary tract. In those cases, a wire stent tends to provide only temporary relief from occlusion because the tumor often tends to grow between the wire struts, eventually resulting in a restenosed passageway. Gianturco U.S. Pat. No. 4,580,568 exemplifies such conventional wire stents. While Gianturco '568 discloses a wire stent to reduce flow defects in arteries, ducts and the like within the body, it does not solve the problem of tissue growth between the wire struts of the stent. Thus, conventional wire stents do not necessarily provide an acceptable long-term solution in the face of malignant tissue growth, nor do such stents provide a means to repair aneurysms percutaneously.
Reference is also made to U.S. patent application Ser. No. 422,606, also by Gianturco. That application teaches a stent structure and method which permits a stent to be easily retrieved from the body percutaneously, some time after being successfully implanted. In many instances, such an advantage would be suitable to the present invention.
There remains a need for a stent assembly that is self-expanding, yet is capable of preventing or reducing restenosis. There is also need for a percutaneous stent assembly which is capable of repairing aneurysms.